So how does going vegan save animals exactly? They simply won't exist if everyone stops eating them and drinking milk. Not sure if many people will want pigs, chickens and cows as pets. 
Its about not beingn part of a system u disagree with. You for example probably dont buy trendy spandezx pants for gym wear or other things you find repulsive. Im trying to go vegan because i dont want to suppprt modern agribusiness for numerous ethical, and environmental reasons that i find important. If u disagree that is totally fine, but dont knock others for trying to make a small impact for what they find important
Being vegan does nothing to harm your way of life. People will always abuse the system and pollute and process shitty meat in inhumane conditions either way, so live your life how u want
Thats a pretty silly argument you presented
You vote when you buy.